The pre-amplifier I am looking to keep is an Audio Research Ref 3. My decision to sell the CJ and keep the AR is based on system integration and personal music and listening preferences. The two amps are both of superb quality and broadly similar price point, but have a different sonic character, being at quite different positions on the dark-bright spectrum. The CT5 is a darker sounding amp and the Ref 3 is brighter, as you are probably aware. How bright (or dark) each sounds within one’s own system will depend on which other components, speakers, cables they are used with, the room etc. In my system, I found the CT5 to be beautifully smooth and have an incredible ability to ‘immerse me in the music’ in a way that is ‘not in my face’, to borrow the description one reviewer used which i think sums up my experience well. The timbres and musicality in my system are superb with the CJ, and music such as jazz can be incredibly relaxing, and mesmerizing. The AR is more prominent in the treble and is strong on presenting all of the micro-detail. It immerses me in the music in a livelier and more energising and front row kind of way. So my experience has been that the two amps are basically just different. I have diverse music interests and prefer the CJ for listening to some types of music, such as Jazz, and the Ref 3 for other types such as rock music. I listen to the latter more often so thats what ended up swaying me to keep the Ref 3. Both are great amps at broadly similar price points that well exceeded 10k when new in Australia. Have you received your CT5 yet? Cheers

Congrats on your purchase Big Dog RJ! The Conrad Johnson CT5 is certainly a great pre-amplifier. If anyone else is interested in this amplifier, I have one in classifieds; https://www.stereo.net.au/forums/topic/255833-fs-conrad-johnson-ct5-preamp/?tab=comments#comment-4001349

I foolishly went into a JB store a few weeks ago and asked an attendant where the SACDs are. She replied that they stopped selling them a couple of years back at that store because no one was buying them. I guess that is understandable if they are not making any money out of them. And besides, most people would need components to play them at home

I received Clay's 9v 4A Kraftwerk last Thursday and after giving it a good few days to burn it, have now had a chance to compare it to my SOTM SPS-500 PSU in powering an SOTM SMS-200 Ultra Neo 9v into a Gieseler GroB DAC, AR Ref 3, JC1 monoblocks and Osborn Epitome's.
Similar to what @lumholtzii mentioned in relation to the 12v 4A version of the Kraftwerk, I found the 9v version to produce a warm, musical, sound. It is warmer and a little darker than the SPS-500, giving vocals and certain instruments a richer sound with more body. In some cases the bass was a little more authoritative.
On some tracks I found this provided a more enjoyable overall listening experience. For example, the second track of the Hoff Ensemble’s Quiet Winter Night DSD was more musical overall and a little more coherent in how instruments were placed. On Go Go Penguin's track 'Prayer', the piano sounded more natural and full bodied with the Kraftwerk. The warmer sound of the Kraftwerk was particularly well suited to tracks that were leaner or had a lot of top-end energy.
However, I also found the SPS-500 to provide a more enjoyable listening experience on some other tracks. The main reason for this is that in my system the SOTM PSU tended to produce a slightly more three dimensional soundstage. While the Kraftwerk produced excellent depth, there was more going on within the soundstage when using the SOTM, including extension of the stage outside the main speakers, and front/back separation of instruments and sounds (e.g. Prayer). While the Kraftwerk provided a more distinct and coherent separation of instruments etc in some tracks, the SOTM was more coherent, detailed, or clearer on others (e.g. Etana's 'Reggae').
@frednork was present for one of the listening sessions. The main thrust of his observations, unprompted by myself, were similar to mine.
Both the SPS-500 and Kraftwerk 9A are clearly excellent PSU's and way better than the PSU that came standard with the Ultra. Overall, I am preferring the SOTM by a small margin in my system mainly because it seems to integrate well with other components in producing an interesting soundstage. But I think which PSU provides the best overall SQ for those needing 9v will be system dependant. For example, the warmer tonal balance of the Kraftwerk will be especially well suited to systems that would benefit from a bit more warmth.
Given the fact that the Kraftwerk is less than half the cost of the SPS-500, it is clearly better value for money.
Given @Snoopy8 and others' reviews of the 12v version of the Kraftwerk, it is clear that Clay is onto a winner with his Kraftwerk series of PSU's!

I was imagining just playing one of my favourite test tracks two or three times using one power supply and then swapping power supply and repeating, and then repeating that process again for same song as necessary until I feel I have sussed the differences on that track, before moving onto a different type of track. At least that’s what I tend to do. But I certainly wouldn’t claim it is seamless. Open to other suggestions that people may have. Interested to hear more about how you use your iPhone.

Thanks @NKMA. Good to hear you have experienced an improvement with the Kraftwerk. My system has tended to be a bit on the bright side and I have deliberately chosen some components to be more laid back as a result. I didn’t realise the SPS-500 may also be a little laid back! Before I decide between the two approaches I mentioned in my above post it is probably desirable that I give the Kraftwerk a test run in my system if possible before committing the $.

I’m planning on getting an Iso Regen and will need a new power supply for it. Main options I’m considering are buying Clay’s multi voltage 3A supply for the Iso and keeping my SOTM SPS-500 on the SMS-200 Ultra Neo, or using the SPS-500 for the Iso and getting Clay to make a 9v 4A Kraftwerk for the Ultra. Based on your review the latter might be better, but I’d prefer to at least compare SPS-500 and 4A in my own system first. Fortunately I know someone who might be able to help with that! [emoji3]

Thanks [mention=135634]frednork[/mention]. Yes this amp is beautifully smooth and as the stereophile review below states it really involves you into the music. https://www.stereophile.com/tubepreamps/706cj/index.html https://forum.audiogon.com/discussions/review-conrad-johnson-ct5-tube-preamp

Clay’s 3A multiple voltage PSU is not the only higher current Gieseler option for driving a 9V Device such as 9V version of SMS-200 Ultra. He can just as easily make a 9V version of the 4A Kraftwerk. He advised me that the only difference is a single resistor, and the “performance would be identical to the 12v 4A unit but just now at 9v out”. So those running a 9V device effectively have a choice of the multiple voltage 3A or the 4A Kraftwerk.